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Tumor Biology

, Volume 35, Issue 5, pp 4277–4284 | Cite as

BRCA1 promoter hypermethylation and protein expression in ovarian carcinoma—an Indian study

  • V. Shilpa
  • Rahul Bhagat
  • C. S. Premalata
  • V. R. Pallavi
  • G. Ramesh
  • Lakshmi KrishnamoorthyEmail author
Research Article

Abstract

Mounting evidences suggest that aberrant methylation of CpG islands is a major pathway leading to the inactivation of tumour suppressor genes and the development of cancer. The aim of the current study was to examine the prevalence of the promoter hypermethylation and protein expression of the BRCA1 gene in epithelial ovarian carcinoma (EOC) to understand the role of epigenetic silencing in ovarian carcinogenesis. We studied the promoter methylation of the BRCA1 gene by methylation-specific PCR in a cohort of 88 patients with EOC, 14 low malignant potential (LMP) tumours and 20 patients with benign tumours of the ovary. The expression of the BRCA1 protein by immunohistochemical analysis was carried out in a subset of 64 EOCs, 10 LMP tumours, 10 benign tumours and 5 normal ovarian tissues. The frequencies of methylation in EOCs and LMP tumours were 51.2 and 57 %, respectively, significantly higher (p = 0.000 and p = 0.001) in comparison to benign tumours and normal ovarian tissue where no methylation was seen. Expression of BRCA1 was significantly lower in EOCs (p = 0.003). Lack of protein expression correlated with tumour grade and type. The methylation status correlated well with downregulation of BRCA1 expression. Our results clearly demonstrate that hypermethylation of BRCA1 promoter is a frequent event in ovarian cancer. These data support the hypothesis that BRCA1 promoter methylation plays an important role in the functional inactivation of BRCA1. Follow-up clinical data will reveal the impact of BRCA1 methylation on survival.

Keywords

Ovarian carcinoma Promoter methylation BRCA1 Protein expression 

Notes

Acknowledgments

The authors thank Dr Sanjay Navani for helping in construction of tissue microarray. We also thank Mr Prashant and Mr Shivshankar for their help in immunohistochemical staining of tissue microarray slides. We are grateful to Dr V Shanmugam (Research Assistant, NIMHANS) for helping with the statistical analysis.

Source of financial support

This study was not supported by any funding agency.

Conflicts of interest

None

References

  1. 1.
    Greenlee RT, Hill-Harmon MB, Murray T, Thun M. Cancer statistics. C A Cancer J Clin. 2001;51:15–36.CrossRefGoogle Scholar
  2. 2.
    Cannistra SA. Cancer of the ovary. N Engl J Med. 1993;329:1550–9.CrossRefPubMedGoogle Scholar
  3. 3.
    Link Jr CJ, Reed E, Kohn EC, Sarosy G. Borderline ovarian tumors. Am J Med. 1996;101:217–25.CrossRefPubMedGoogle Scholar
  4. 4.
    Scully RE. WHO classification and nomenclature of ovarian cancer. J Natl Cancer Inst Monogr. 1975;42:5–7.Google Scholar
  5. 5.
    Cliby W, Ritland S, Hartmann L, et al. Human epithelial ovarian cancer allelotype. Cancer Res. 1993;53:2393–8.PubMedGoogle Scholar
  6. 6.
    Sato T, Saito H, Morita R, et al. Allelotype of human ovarian cancer. Cancer Res. 1991;51:5118–22.PubMedGoogle Scholar
  7. 7.
    Bird A, Wolffe AP. Methylation-induced repression—belts, braces and chromatin. Cell. 1999;99:451–4.CrossRefPubMedGoogle Scholar
  8. 8.
    Wei SH, Chen CM, Strathdee G, et al. Methylation microarray analysis of late-stage ovarian carcinomas distinguishes progression-free survival in patients and identifies candidate epigenetic markers. Clin Cancer Res. 2002;8:2246–52.PubMedGoogle Scholar
  9. 9.
    Pérez-Vallés A, Martorell-Cebollada M, Fuster-Diana E, García-García JA, Nogueira-Vázquez E. The usefulness of antibodies to the BRCA1 protein in detecting the mutated BRCA1 gene. An immunohistochemical study. J Clin Pathol. 2001;54:476–80.CrossRefPubMedPubMedCentralGoogle Scholar
  10. 10.
    Yoshida K, Miki Y. Role of BRCA1 and BRCA2 as regulators of DNA repair, transcription, and cell cycle in response to DNA damage. Cancer Sci. 2004;95:866–71.CrossRefPubMedGoogle Scholar
  11. 11.
    Jazaeri AA, Yee CJ, Sotiriou C, et al. Gene expression profiles of BRCA1-linked, BRCA2-linked, and sporadic ovarian cancers. J Natl Cancer Inst. 2002;94:990–1000.CrossRefPubMedGoogle Scholar
  12. 12.
    Bozzetti C, Bortesi B, Merisio C. Loss of heterozygosity (LOH) in ovarian cancer. Int J Gynaecol Obstet. 2004;85:294–5.CrossRefPubMedGoogle Scholar
  13. 13.
    Rice JC, Massey-Brown KS, Futscher BW. Aberrant methylation of the BRCA1 CpG island promoter is associated with decreased BRCA1 mRNA in sporadic breast cancer cells. Oncogene. 1998;17:1807–12.CrossRefPubMedGoogle Scholar
  14. 14.
    Weberpals JI, Tu D, Squire JA, Pelletier LB, Amin MS, Islam S, et al. Breast cancer 1 (BRCA1) protein expression as a prognostic marker in sporadic epithelial ovarian carcinoma: an NCIC CTG OV.16 correlative study. Ann Oncol. 2011;22(11):2403–10.CrossRefPubMedGoogle Scholar
  15. 15.
    Xu CF, Brown MA, Chambers JA, Griffiths B, Nicolai H, et al. Distinct transcription start sites generate two forms of BRCA1 mRNA. Hum Mol Genet. 1995;4:2259–64.CrossRefPubMedGoogle Scholar
  16. 16.
    Allred DC, Harvey JM, Berardo M, Clark GM. Prognostic and predictive factors in breast cancer by immunohistochemical analysis. Mod Pathol. 1998;11:155–68.PubMedGoogle Scholar
  17. 17.
    Berger J, Daxenbichler G. DNA methylation of nuclear receptor genes—possible role in malignancy. J Steroid Biochem. 2002;80:1–11.CrossRefGoogle Scholar
  18. 18.
    Miranda TB, Jones PA. DNA methylation: the nuts and bolts of repression. J Cell Physiol. 2007;213(2):384–90.CrossRefPubMedGoogle Scholar
  19. 19.
    Bianco T, Chenevix TG, Cooper JE, Dobrovic A, Walsh DC. Tumour-specific distribution of BRCA1 promoter region methylation supports a pathogenetic role in breast and ovarian cancer. Carcinogenesis. 2000;21(2):147–51.CrossRefPubMedGoogle Scholar
  20. 20.
    Baldwin RL, Nemeth E, Cass I, Karlan BY, Narod S, Shvartsman H, et al. BRCA1 promoter region hypermethylation in ovarian carcinoma: a population-based study. Cancer Res. 2000;60:5329–33.PubMedGoogle Scholar
  21. 21.
    Esteller M, Silva JM, Bonilla F, Dominguez G, Lerma E, Matias-Guiu X, et al. Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors. J Natl Cancer Inst. 2000;92:564–9.CrossRefPubMedGoogle Scholar
  22. 22.
    Dhillon VS, Aslam M, Husain SA. The contribution of genetic and epigenetic changes in granulosa cell tumors of ovarian origin. Clin Cancer Res. 2004;10:5537–45.CrossRefPubMedGoogle Scholar
  23. 23.
    Wiley A, Katsaros D, Beeghly A, Chen H, Puopolo M, Rigault de la Longrais IA, et al. Aberrant promoter methylation of multiple genes in malignant ovarian tumors and in ovarian tumors with low malignant potential. Cancer. 2006;107:299–308.CrossRefPubMedGoogle Scholar
  24. 24.
    Mancini DN, Rodenhiser DI, Ainsworth PJ, et al. CpG methylation within the 5′ regulatory region of the BRCA1 gene is tumor specific and includes a putative CREB binding site. Oncogene. 1998;16(9):1161–9.CrossRefPubMedGoogle Scholar
  25. 25.
    Jiaze A, Qingyi W, Gordon BM, Karen HL, Li-E W, Xi C, et al. Messenger RNA expression and methylation of candidate tumor-suppressor genes and risk of ovarian cancer—a case–control analysis. Int J Mol Epidemiol Genet. 2010;1(1):1–10.Google Scholar
  26. 26.
    Chan QK, Khoo US, Chan KY, et al. Distinct hypermethylation profile of primary breast cancer is associated with sentinel lymph node metastasis. Clin Cancer Res. 2005;11:2156–62.CrossRefGoogle Scholar
  27. 27.
    Pan Y, Wu Y, Zhu X, Shi Y. Methylation of tumor suppressor gene RASSF1A and BRCA1 in primary epithelial ovarian cancer. Sci Res Essays. 2010;5(24):3939–44.Google Scholar
  28. 28.
    Press JZ, De Luca A, Boyd N, et al. Ovarian carcinomas with genetic and epigenetic BRCA1 loss has distinct molecular abnormalities. BMC Cancer. 2008;8:17.CrossRefPubMedPubMedCentralGoogle Scholar
  29. 29.
    Wang C, Horiuchi A, Imai T, et al. Expression of BRCA1 protein in benign, borderline, and malignant epithelial ovarian neoplasms and its relationship to methylation and allelic loss of the BRCA1 gene. J Pathol. 2004;202(2):215–23.CrossRefPubMedGoogle Scholar
  30. 30.
    Wilcox CB, Baysal BE, DeLoia JA, Gallion HH, Strange MA. High-resolution methylation analysis of the BRCA1 promoter in ovarian tumors. Cancer Genet Cytogenet. 2005;159(2):114–22.CrossRefPubMedGoogle Scholar

Copyright information

© International Society of Oncology and BioMarkers (ISOBM) 2014

Authors and Affiliations

  • V. Shilpa
    • 1
  • Rahul Bhagat
    • 1
  • C. S. Premalata
    • 2
  • V. R. Pallavi
    • 3
  • G. Ramesh
    • 1
  • Lakshmi Krishnamoorthy
    • 1
    • 4
    Email author
  1. 1.Department of BiochemistryKidwai Memorial Institute of OncologyBangaloreIndia
  2. 2.Department of PathologyKidwai Memorial Institute of OncologyBangaloreIndia
  3. 3.Department of Gynaec OncologyKidwai Memorial Institute of OncologyBangaloreIndia
  4. 4.Department of BiochemistrySri Shankara Cancer Hospital & Research CentreBangaloreIndia

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